Looper mechanism



Oct. 23, 1962 w, RUSSELL ETAL 3,059,600

LOOPER MECHANISM Filed Dec. 4, 1959 mu wee Ns Ess w IRE W h e a Wk am HEW 3,059,609 Ice Patented Oct.-23, 1952 3,059,600 LOOPER MECHANISM Harvey W. Russell, Nyacis, and Richard H. Russell, Tappan, N.Y., assignors to Willcox & Gibbs Sewing Machine Company, New York, N.Y., a corporation of New York Filed Dec. 4, 1959, Ser. No. 857,392 4 Claims. (Cl. 112-200) This invention relates to improvements in looper mechanisms for sewing machines and to methods for moving the looper relative to the needle assembly thereof. More specifically, it constitutes an improvement over the invention disclosed in the patent to Russell et al., No. 2,834,309.

Prior to the present invention and as seen in the aforenoted patent, looper mechanisms for cooperation with the needle assembly of sewing machines were complicated devices including many parts which tended to increase the operable weight of the device and slow its operation. While prior art devices were eflicient and served their required purpose when operating at normal speeds, they tended to become sluggish and lost efiiciency at high speed operation, such as over 5000 rpm.

The present invention overcomes the problems aforenoted and provides a looper mechanism for sewing machines of reduced operable weight, which is adapted to operate at high speed with increased efficiency.

It is an object of the invention to provide a looper mechanism or the like having a substantially reduced number of parts, whereby the operable weight of the device is reduced to facilitate high speed operation.

It is also an object of the invention to provide a looper mechanism which eliminates long sliding bearings and the like to increase the speed of operation and reduce the slowing effect of friction thereon.

Another object of the invention is to provide a looper mechanism and method, whereby the looper is operated in an elliptical path relative the needle assembly in timed relation to the operation of the sewing machine, and in which dwell at the end of the looper stroke is substantially reduced.

Still another object of the invention is to provide a looper mechanism, wherein the looper assembly is movably carried by a pivotally mounted looper support, in which the support, in which the support is rocked about its pivot and the looper assembly is moved relative to the support by separate means carried by the main drive shaft of the sewing machine so that simultaneous transverse and longitudinal movement is imparted to the looper relative the needle asembly.

Yet another object of the invention is to provide a method for moving a looper in an elliptical or simultan eous transverse and longitudinal path relative to the needle assembly of a sewing machine, where the steps of the method include rocking the support for the looper by operably connecting it to the main drive shaft of the sewing machine and moving the looper relative its support in a direction transverse to the rocking thereof by separately connecting it to the main drive shaft.

It is further an object ofvthe invention to provide a looper mechanism wherein the looper is positively moved in a simultaneous traverse and longitudinal path relative the needle assembly and in which the length and position of the longitudinal stroke of the looper is readily adjustable.

It is still further an object of the invention to provide a looper assembly of simple construction, embodying but a relatively few parts, that is accurate at high speed operation and is of such rugged character it will function over a long period of time with freedom from all difficulty.

Other objects and advantages will be apparent from the specification and claims when considered in connection with the attached sheet of drawings, illustrating one form of the invention, wherein like characters represent like parts and in which:

FIGURE 1 is a fragmentary side elevational view of the looper mechanism of the invention;

FIG. 2 is a fragmentary front elevational view taken in the direction of the arrows 2-2 in FIG. 1;

FIG. 3 is a fragmentary sectional view of the transverse looper drive taken in the direction of the arrows 3-3 in FIG. 1;

FIG. 4 is a fragmentary sectional view partially in elevation of the looper asseembly mount and longitudinal looper drive taken in the direction of the arrows 44 in FIG. 1; and

FIG. 5 is a diagrammatic illustration taken from above of the elliptical path the looper travels during its operation.

As afo-renoted, the present invention is an improvement on looper mechanisms of the type disclosed in Patent No. 2,834,309, to which reference may be hereinafter made. According to the invention, as shown in FIGS 1 and 2 of the drawings, the looper assembly 10 of the looper mechanism 11 is movably mounted on a looper support 12 which is pivotally carried, as at 13, by a bracket 14 on the frame 15 of the sewing machine. The support 12, which is adapted to be rocked about its pivot 13 to move the looper assembly 10 longitudinally relative the needle assembly 16 of the sewing machine, includes a T-shaped post 17 having a substantially C-shaped looper assembly mounting bracket 18 removably connected to the upper end thereof by machine screws 19, or the like. Formed integral with the lower end of post 17 is a cylindrical shaft bearing 20, for a purpose to be hereinafter explained, and a cylindrical pivot bearing 21. The pivot bearing is rotatably supported on the pivot 13, which may be a rod or the like, extending outwardly of bracket 14 and is retained thereon by a collar 22 in threaded engagement with the end of rod 13. The collar may be locked in position with respect to the rod by means of a set screw 23.

The looper assembly 10 includes one or a plurality of loopers 24, as required, mounted on a looper carrier 25 so as to cooperate with the needles of the needle assembly 16. The looper carrier 25 is connected to a looper mounting shaft 26 that is slidably journaled in bearings 27 formed in the ends of the arms of C-shaped looper assembly mounting bracket 18.

In accordance with conventional practice, the looper or loopers 24 are preferably actuated in predetermined timed relation to the operation of the needle carrier from the main drive shaft 28 of the sewing machine so that the stitches will be properly correlated during the sewing operation. According to the present invention this is accomplished by connecting the looper support 12 to the main drive shaft so that it is rocked about its pivot 13 to move the looper and looper assembly 1t} longitudinally relative to the needle assembly 16 and by separately connecting the looper assembly 141 to the main drive shaft so that the mounting shaft 26 thereof is moved relative to C-shaped bracket 18 and the looper is traveled in a direction transverse to the rocking of looper support 12. It will be understood that the simultaneous rocking of the looper support 12 in a longitudinal path relative the needle assembly 16 and the transverse movement of the looper assembly 111 relative the support combine to travel the looper 24 in an elliptical path relative the needle assembly.

As shown in the drawings, looper support 12 is connected to the main drive shaft 28 of the sewing machine by means of a rocker arm 29 that is rotatably carried, in any manner known to the art, by an eccentric 30 on the main drive shaft. The rocker arm is rotatably connected to a pin 31 carried by the post 17 of looper support 12 and, through engagement with the pin, rocks the support about its pivot 13 as the main drive shaft rotates. As shown most clearly in FIG. 4, the rocker arm 29, which may be longitudinally split, is provided with a rotatable spherical bearing 29a, in the end directed away from the main drive shaft, which is adapted to rotatably receive the pin 31, so that the pin is universally movable relative to the arm to prevent binding or other interference with the operation of the looper mechanism.

While pin 31 may be formed integral with post 17 or may be immovable relative thereto, in the illustrated form of the invention the pin is adjustably carried in an elongate slot 32 formed in the post and is eccentric in shape, whereby adjustment of the length and position of the longitudinal stroke of the looper may be achieved. The slot 32, which is slightly arced, is substantially vertically disposed so that the adjustment of the pin in the slot to shorten or lengthen the operable length of the pivot arm, or the distance between pin 31 and pivot 13, will lengthen or shorten, respectively, the length of the longitudinal stroke of the looper. The pin 31 is eccentric in shape, having the axis of the rocker arm engaging portion 31a parallel to and offset from the axis of the looper support engaging portion 3111. Between the portion 31a and 31b of the pin, an integral flangelike washer 310 is provided for engaging the post 17 at one side of the slot 32 and the end of portion 31b directed away from portion 31a is adapted to removably receive a Washer 31d and is threaded for engagement by a nut 31e, which facilitates locking the pin in adjusted position in slot 32. It will be seen that, in addition to the adjustment of the length of the longitudinal stroke of the looper, the position of the path of travel of the looper may be adjusted by rotating the eccentric pin 31 in the slot 32 so that the rocker arm engaging portion 31a is farther or nearer to the main drive shaft 28 of the sewing machine, whereby the entire path of travel of the looper is shifted relative the needle assembly, respectively, toward or away from the main drive shaft.

The looper assembly 10, which as aforenoted, is adapted to be moved transversely of the looper support 12, is connected to an eccentric 33 on the main drive shaft 28. As shown, a shaft 34 rotatably carried in cylindrical shaft bearing of looper support 12 is connected to the looper mounting shaft 26 through a yoke 35 having a drum 36 rotatably carried in the upper end thereof. The drum 36 is connected through a pin 37 to a clamp 38 adjustably connected to the looper mounting shaft 26. The yoke 35, while it may be formed integral with shaft 34, is shown as being mounted on an end of the shaft and locked thereto by means of a set screw 39. The opposite end of rotatable shaft 34 is connected to the ecnentric 33 of the main drive shaft to be rotated thereby. As seen most clearly in FIG. 3 a link 40 has one cut thereof connected to the shaft, as by a split clamp connection or the like, and has its other end connected by means of a ball and socket connection shown at 41, to an arm 42 rotatably carried by the eccentric 33 of main drive shaft 28. It will be seen that as main drive shaft 28 rotates, rotary movement is imparted to shaft 34 through arm 42 and link 40 whereby yoke 35 is reciprocated to move looper mounting shaft 26 and consequently looper 24 back and forth transverse to the path of movement of looper support 12.

Referring now to FIG. 5, wherein the path of travel of looper 24 is diagrammatically shown, it will be seen that the combined longitudinal and transverse movement of the looper, as provided by the combined separate rocking of the looper support 12 and shifting of looper assembly 10 relative to the support, causes the looper to move, in the direction of the arrows, in an elliptical path having minimum dwell at the ends of the stroke. The elongate elliptical path of travel of the looper, resulting from the separate operation of the component elements of movement forming the ellipse, facilitates the high speed operation of the sewing machine by providing a sufficient looper stroke length to achieve the desired results. The reduction in dwell at the ends of the looper stroke, resulting from the elimination of the long sliding bearing utilized in the prior art eliminates sluggishness in the operation of the looper mechanism at high speed and facilitates smooth cooperative coaction between the needle assembly and the looper mechanism.

Thus, among others, the several objects and advantages of the invention as aforenoted are achieved. Obviously numerous changes in the structure may be resorted to without departing from the spirit of the invention as defined by the claims.

We claim:

1. A looper mechanism for sewing machines having a frame carrying a main drive shaft and needle assembly operably connected to said main drive shaft comprising a looper support means pivotally connected to said frame, a looper assembly movably carried by said support for movement in an elliptical path resulting from a combination of an arcuate longitudinal and straight line transverse movement about the path of movement of said needle assembly in timed relation to the operation of said sewing machine, a rocker arm directly connected to said looper support means and directly eccentrically carried by said main drive shaft for rocking said looper support about its pivot to impart said arcuate longitudinal movement thereto, separate pivotal means connected to the looper assembly, eccentric means connected to the main drive shaft and said separate means to oscillate the separate means about its pivot for imparting transverse movement to the looper assembly relative to the support, and means for controlling said looper assembly to maintain said straight line movement of the assembly during said transverse movement thereof.

2. A looper mechanism for sewing machines having a frame carrying a main drive shaft and needle assembly operably connected to said main drive shaft comprising a looper support means pivotally connected to said frame, a looper assembly movably carried by said support for movement in an elliptical path resulting from a combination of longitudinal and transverse movement about the path of movement of said needle assembly in timed relation to the operation of said sewing machine, a rocker arm having an adjustable pin and slot connection to said looper support means and directly eccentrically carried by said main drive shaft for rocking said support means about its pivot to impart said longitudinal movement thereto, separate means connected to the looper assembly, and eccentric means connected to the main drive shaft and the separate means to oscillate the separate means for imparting transverse movement to the looper assembly relative to the support.

3. A looper mechanism for sewing machines having a frame carrying a main drive shaft and needle assembly operably connected to said main drive shaft comprising a looper support means pivotally connected to said frame, a looper assembly movably carried by said support for movement in an elliptical path resulting from a combination of longitudinal and transverse movement about the path of movement of said needle assembly in timed relation to the operation of said sewing machine, a rocker arm directly eccentrically carried by said main drive shaft and having a connector including a pin cooperating with a ball joint in said rocker arm and eccentric to an adjustable pin and slot connection to said looper support means for rocking said support means about its pivot to impart said longitudinal movement thereto and for adjusting the position and amount of longitudinal movement of said looper assembly, separate means connected to the looper assembly, and eccentric means connected to the main drive shaft and the separate means to oscillate the separate means for imparting transverse movement to the looper assembly relative to the support.

4. A looper mechanism for sewing machines having a frame carrying a main drive shaft and needle assembly operably connected to said main drive shaft comprising a looper support means pivotally connected to said frame, a looper assembly including a looper mounting shaft slidably mounted in aligned bearings on the support means, a looper carrier movably carried by said mounting shaft and adapted to be moved in an elliptical path resulting from a combination of longitudinal and transverse movement about the path of movement of said needle assembly in timed relation to the operation of said sewing machine, a rocker arm directly connected to said looper support means and directly eccentrically carried by said 15 main drive shaft for rocking said support about its pivot to impart said longitudinal movement thereto, separate means connected to the looper assembly, eccentric means connected to the main drive shaft and the separate means to oscillate the separate means, and a pin operating in a slotted pivoted drum connecting the separate means to the looper mounting shaft for imparting straight line transverse movement to the looper assembly relative to the support.

References Cited in the file of this patent UNITED STATES PATENTS 580,015 Staples Apr. 6, 1897 903,749 Miller Nov. 10, 1908 1,190,959 Seymour July 11, 1916 2,834,309 Russell et a1. May 13, 1958 FOREIGN PATENTS 888,199 Germany Aug. 31, 1953 

